情态动词归纳性讲解

1、1情态动词I. 种类：1）只能作情态动词：can, must, ought to, may2）既能情又助： will, shall, would, should3）既情又行为： need, dare4）短语： be able to, have to, used to, had better, would ratherII. 用法：1.表猜测，可能性： must, may, might, can, could1） must 表肯定 “猜测” （指说话人看来一定是，必然是 ）只能用 在肯定句中：It must be headmaster.Your father must be nearly for

2、ty now.还可以用 must be doingHe must be enjoying himself.当 must 表推测是，否定不用 must not,而用 cannotIt cant be headmaster.表必须，一定：（肯定用 must,否定用 mustn t 一定不要，表 禁止）You mustn t smoke here.2） may, can 表可能在肯定句中 may 表示事实上的可能性， （某事将发生的实际可 能性。 ）can 表示逻辑上的可能性：比较： The road may be blocked.（=It is possible that the road isb

3、locked.=Perhapsthe road is blocked.）由于某种原因路可能被 阻塞了。The road can be blocked.（= It is possible for the road to beblocked It is possible to block the road 根 据逻辑推理表示可能 会出现某种情况，并不牵涉具体的事情是否会发生。Accidents can happen on such a rainy day.比较：Mr. Li looks pale. He may be ill.（事实上的可能性）Mr. Li isin poor health. He

4、 can be ill at any time. （逻辑 上的可能性）在否定和疑问句中， 便不存在这种“事实上的可能性” 和“逻 辑上的可能性”的区别，因为在否定句和疑问句中，通常是 用 can而不是用 may 表示可能。We may go camp ing n ext Sun day.（事实）Will you answer the doorbell? It may be your father.This may/ might/ could be done by him.Can it be true?What can he be thinking of?3）can, could （一般用于疑问

5、和否定句或感叹句中表惊异，怀2疑，不相信的推测 ）可能，能够This can t be done by him.This may not be done by him.弱）Can this be done by him?How can he so rude to others?He cantbe more than thirty.5） 情态动词加原形表对一般情况的猜测，但 would, could, might 并不一定与过去时间有关， 而表示可能性弱于它们相应的现 在时形式。He may/ might be a student.He cant / couldnt be a student.6

6、） 时态： can, may, mustca n/ may/ must +do 对现在或将来的动作进行推测can/ may/ must + be doi ng 是对眼下正在进行的动作进行推测 can/ may/ must + have done 是推测过去时间可能发生的事情 must/may/might have done （肯定） cant/ couldnthave done （否定）could/ canhave done （疑问） They may have settled theproblem.I might have come to a wrong conclusion.The roa

7、d isntwet. It canthave rained last night.Could Mary have missed the first bus? She got up very early.7） 反意问句：情态动词表推测，不用情态动词反问，具体根据 后面的时态而定：It must have rained last night, didntit?He must have told you about it, hasnthe?8）should 推断的“应该会”不是责任、义务的应该-When will I get this photos?-They should be ready by

8、12 oclock.Its 12 oclock. He should come back at any moment.Should= ought to 应该Should / ought to have done 本应该Should 还可译成“竟然”You cant imagine that a well-behaved gentleman _ be so rudeto a lady. A. might B. need C. should D. would3【1】You _ be tired - youve been working for an hour. A. must notB. wont

9、 C. cant D. may not【2】 -Excuse me. Is this the right way to the Summer Palace? -Sorry,I am not sure,. But it _ be. A. might B. will C. must D. can【3】You might just as well tell the manufacturer that male customs _not like the design of the furniture. A. must B. shall C. may D.need【4】 -Isnt that Anns

10、 husband over there? -No, it _ be him-Imsure he doesnwtear glasses. A. cant B. mustnt C. wont D. maynot【5】 -Who is the girl standing over there ? -Well, if you _ know, hermane id Mabel. A. may B. can C. must D. shall【6】2.(表允许 )可以 may, can , might1) may 在陈述句中， may 表示“许可”，通常是指说话人给予的 许可，口语中可以用 can 例：Yo

11、u may / can smoke in this room.=You are permitted (by me) to You may / can come if you wish.否定用 may not 表示说话人不许可，例：You may not go. (= I dont permit you to.)May not 也可表示一般的不许可，即表示根据一般规定而不是 说话人不许可：例：Borrowers may not take out of the library more than two books at atime.Can 可以用来表示普遍的许可，即不指明是谁给予的许可 :You

12、 can keep the book for more than two weeks.May 在疑问句或 if 从句中 ,may 不是说话人给予的许可，而 是征询听话人的许可，例：May I征询对方许可比较正式，在口气上比较客气，在口语 中用Can I?May / Can I smoke in this room? (= Will you allow me to )May I go now?再问客观上是否允许时用 can 时更多一些，如：Can we take the books out of the room?2) might, could, would 表请求许可时 ,不表过去，只是语气更

13、加委 婉，客气。Might I have a look at your new dictionary?4-Could / might I use your bike tomorrow morning?-Yes, you can/ may.No, I m afraid not.不能用 ： Yes, you could/ might.3) shall 在疑问句中用于一，三人称表征询听话人的意见或意图，如:Shall I carry your suitcase? (=Do you want me to carry yoursuitcase?Shall we have dinner? (=Do you

14、 agree to our having dinner now)Where shall I wait for you?Shall we sit here?Shall he come to see you?要不要他来看你？4) will 在疑问句中用于第二人称 ,表示请求(请对方做某事) would 更加委婉Will you help me with my English?Will you sing at the concert tomorrow evening?Would you tell me the way to the station? 必须用 would 的场合Would you li

15、ke/prefer/ love to go with me?Would /Do you mind if I open the door?3. 表能力： can 和 be able to 都表能力1) be able to 主语必须是人或动物，而 can 没有这个限制。He can swim. = He is able to swim.The radio can be fixed in 30 minutes.不能用 be able to)2) be able to 可以有任何形式，而 can 只有过去式 could He will be ableto skate as well as you.T

16、he foreigners come to China without being able to speak Chinese.3) be able to 的过去式(was/were able tc)可作“设法做成某事讲相当于 manage to do 或 succeed in doingWith the help of the firemen, they were able to leave the burninghouse.(were able to 不能换成 could.)4.表必须 must, have to, shall must 说话人的主观意志，或要求某人必须做某事. have

17、to 表客观需要例： I must go now, or I llbe late.shall 用于二，三人称表允诺，警告，命令，决心，强制Don worry. You shall get the an swer this after noon 允诺）He shall be sorry for it one day. （警告） Nothi ng shall stop us fromcomi ng.（决丿心）5. will, would51）表意愿（用于陈述句，可用于各种人称,有时态变化）I will stop smoking.-Give my regards to your family.-Of

18、 course, I will.I wished him to give up smoking, but he wouldntlisten.2）表功能，有时态变化The door wontopen.My radio wontwork.6. 表习惯性动作： will, would ; used to “总是” “惯于”I will sit here for several hours.would / used toWhen I was a child, I would / used to get up early and go fishing.There used to a river in t

19、he village. 不（ 能用 would）7. 回答问句时有变化的情态动词：1）Must we hand in our homework today?-Yes, you must.No, you neednt.you donthave to2）-May I take this book out of the reading-room?-Yes, you may.No, you mustnt.you may not. youdbetter not.3）-Need you go now?-Yes, I must.-No, you neednt.4）Could you expla in it

20、to me? Yes, I will.（愿意）Could I use yourbook? Yes, you can. （不用 could）5）Shall I tell him about it? No, you neednt. I have told him.Shall I invite him to go with us? No, you mustnt. I dontwant to seehim again.6）Would you mind opening the door? No, indeed. （Of course not./Certainly not. / Not at all.)若

21、 Would you mind my opening the door? No, go ahead.7. need; dareHe doesnt dare ( to) answer.6Does he dare to go?Dont you dare ( to) touch it?8.情态动词 + have done1) should have done 本应该ought to have doneshouldnt have doneYou should have handed in your home work on time.-Mary looks sad. Did you tell her about the accident.-Yes,